Bilbo puts on the One Ring to evade the Sackville-Bagginses (estimated date)

[Said Merry,] 'It was the Sackville-Bagginses that were his downfall.... One day, a year before the Party, I happened to be walking along the road, when I saw Bilbo ahead. Suddenly in the distance the S.-B.s appeared, coming towards us. Bilbo slowed down, and then hey presto! he vanished. I was so startled that I hardly had the wits to hide myself in a more ordinary fashion; but I got through the hedge and walked along the field inside. I was peeping through into the road, after the S.-B.s had passed, and was looking straight at Bilbo when he suddenly reappeared. I caught a glint of gold as he put something back in his trouser-pocket.